A Swedish scientific research team has determined that health issues as minor as inflammation and as serious as cancer may be linked to cardboard packaging made from recycled newspapers.

The health risks comes from mineral oils in newspaper ink that survive the recycling process, leaking into foods commonly sold in cardboard boxes such as breakfast cereal, grains, pastas, crackers and cookies. The toxins were even found passing through the inner plastic liner bags, says researchers at the Food Safety Laboratory in Zurich, who tested 119 products from German supermarkets, with 90 of the packages containing higher than normal levels of mineral oils.

The research team cited that toxicological testing (on lab rats) had linked these mineral oils to increased health complaints with potentially serious consequences.

While official health organizations throughout Europe and the UK have said it’s no reason for alarm at this stage, a UK industry body, The Food and Drink Federation, has called for an investigation, “We understand that the information currently available is limited and we are working with the Food Standards Agency, food manufacturers, retailers and the packaging supply chain to gather more information,” said Barbara Gallani, FDF director of food safety and science.

In the U.S., recycled paper cardboard is a staple among many food manufacturers, especially in light of issues with BPA (bisphenol A) plastics, known for leaching endocrine adaptors into foods and being linked to serious illnesses. Another report earlier this month revealed that BPA-free plastics, thought to be more stable and safer, have been shown to also leach toxins into foods.